Slippery slopes are themselves a slippery concept. Imagine trying to explain them to an alien:

"Well, we right-thinking people are quite sure that the Holocaust happened, so banning Holocaust denial would shut up some crackpots and improve the discourse. But it's one step on the road to things like banning unpopular political positions or religions, and we right-thinking people oppose that, so we won't ban Holocaust denial."

And the alien might well respond: "But you could just ban Holocaust denial, but not ban unpopular political positions or religions. Then you right-thinking people get the thing you want, but not the thing you don't want."

This post is about some of the replies you might give the alien.

Abandoning the Power of Choice

This is the boring one without any philosophical insight that gets mentioned only for completeness' sake. In this reply, giving up a certain point risks losing the ability to decide whether or not to give up other points.

For example, if people gave up the right to privacy and allowed the government to monitor all phone calls, online communications, and public places, then if someone launched a military coup, it would be very difficult to resist them because there would be no way to secretly organize a rebellion. This is also brought up in arguments about gun control a lot.

I'm not sure this is properly thought of as a slippery slope argument at all. It seems to be a more straightforward "Don't give up useful tools for fighting tyranny" argument.

The Legend of Murder-Gandhi

Previouslyon Less Wrong'sThe Adventures of Murder-Gandhi: Gandhi is offered a pill that will turn him into an unstoppable murderer. He refuses to take it, because in his current incarnation as a pacifist, he doesn't want others to die, and he knows that would be a consequence of taking the pill. Even if we offered him $1 million to take the pill, his abhorrence of violence would lead him to refuse.

But suppose we offered Gandhi $1 million to take a different pill: one which would decrease his reluctance to murder by 1%. This sounds like a pretty good deal. Even a person with 1% less reluctance to murder than Gandhi is still pretty pacifist and not likely to go killing anybody. And he could donate the money to his favorite charity and perhaps save some lives. Gandhi accepts the offer.

Now we iterate the process: every time Gandhi takes the 1%-more-likely-to-murder-pill, we offer him another $1 million to take the same pill again.

Maybe original Gandhi, upon sober contemplation, would decide to accept $5 million to become 5% less reluctant to murder. Maybe 95% of his original pacifism is the only level at which he can be absolutely sure that he will still pursue his pacifist ideals.

Unfortunately, original Gandhi isn't the one making the choice of whether or not to take the 6th pill. 95%-Gandhi is. And 95% Gandhi doesn't care quite as much about pacifism as original Gandhi did. He still doesn't want to become a murderer, but it wouldn't be a disaster if he were just 90% as reluctant as original Gandhi, that stuck-up goody-goody.

What if there were a general principle that each Gandhi was comfortable with Gandhis 5% more murderous than himself, but no more? Original Gandhi would start taking the pills, hoping to get down to 95%, but 95%-Gandhi would start taking five more, hoping to get down to 90%, and so on until he's rampaging through the streets of Delhi, killing everything in sight.

Now we're tempted to say Gandhi shouldn't even take the first pill. But this also seems odd. Are we really saying Gandhi shouldn't take what's basically a free million dollars to turn himself into 99%-Gandhi, who might well be nearly indistinguishable in his actions from the original?

Maybe Gandhi's best option is to "fence off" an area of the slippery slope by establishing a Schelling point - an arbitrary point that takes on special value as a dividing line. If he can hold himself to the precommitment, he can maximize his winnings. For example, original Gandhi could swear a mighty oath to take only five pills - or if he didn't trust even his own legendary virtue, he could give all his most valuable possessions to a friend and tell the friend to destroy them if he took more than five pills. This would commit his future self to stick to the 95% boundary (even though that future self is itching to try to the same precommitment strategy to stick to its own 90% boundary).

Real slippery slopes will resemble this example if, each time we change the rules, we also end up changing our opinion about how the rules should be changed. For example, I think the Catholic Church may be working off a theory of "If we give up this traditional practice, people will lose respect for tradition and want to give up even more traditional practices, and so on."

Slippery Hyperbolic Discounting

One evening, I start playing Sid Meier's Civilization (IV, if you're wondering - V is terrible). I have work tomorrow, so I want to stop and go to sleep by midnight.

At midnight, I consider my alternatives. For the moment, I feel an urge to keep playing Civilization. But I know I'll be miserable tomorrow if I haven't gotten enough sleep. Being a hyperbolic discounter, I value the next ten minutes a lot, but after that the curve becomes pretty flat and maybe I don't value 12:20 much more than I value the next morning at work. Ten minutes' sleep here or there doesn't make any difference. So I say: "I will play Civilization for ten minutes - 'just one more turn' - and then I will go to bed."

Time passes. It is now 12:10. Still being a hyperbolic discounter, I value the next ten minutes a lot, and subsequent times much less. And so I say: I will play until 12:20, ten minutes sleep here or there not making much difference, and then sleep.

And so on until my empire bestrides the globe and the rising sun peeps through my windows.

This is pretty much the same process described above with Murder-Gandhi except that here the role of the value-changing pill is played by time and my own tendency to discount hyperbolically.

The solution is the same. If I consider the problem early in the evening, I can precommit to midnight as a nice round number that makes a good Schelling point. Then, when deciding whether or not to play after midnight, I can treat my decision not as "Midnight or 12:10" - because 12:10 will always win that particular race - but as "Midnight or abandoning the only credible Schelling point and probably playing all night", which will be sufficient to scare me into turning off the computer.

(if I consider the problem at 12:01, I may be able to precommit to 12:10 if I am especially good at precommitments, but it's not a very natural Schelling point and it might be easier to say something like "as soon as I finish this turn" or "as soon as I discover this technology").

Coalitions of Resistance

Suppose you are a Zoroastrian, along with 1% of the population. In fact, along with Zoroastrianism your country has fifty other small religions, each with 1% of the population. 49% of your countrymen are atheist, and hate religion with a passion.

You hear that the government is considering banning the Taoists, who comprise 1% of the population. You've never liked the Taoists, vile doubters of the light of Ahura Mazda that they are, so you go along with this. When you hear the government wants to ban the Sikhs and Jains, you take the same tack.

But now you are in the unfortunate situation described by Martin Niemoller:

First they came for the socialists, and I did not speak out, because I was not a socialist.Then they came for the trade unionists, and I did not speak out, because I was not a trade unionist.Then they came for the Jews, and I did not speak out, because I was not a Jew.Then they came for me, but we had already abandoned the only defensible Schelling point

With the banned Taoists, Sikhs, and Jains no longer invested in the outcome, the 49% atheist population has enough clout to ban Zoroastrianism and anyone else they want to ban. The better strategy would have been to have all fifty-one small religions form a coalition to defend one another's right to exist. In this toy model, they could have done so in an ecumenial congress, or some other literal strategy meeting.

But in the real world, there aren't fifty-one well-delineated religions. There are billions of people, each with their own set of opinions to defend. It would be impractical for everyone to physically coordinate, so they have to rely on Schelling points.

In the original example with the alien, I cheated by using the phrase "right-thinking people". In reality, figuring out who qualifies to join the Right-Thinking People Club is half the battle, and everyone's likely to have a different opinion on it. So far, the practical solution to the coordination problem, the "only defensible Schelling point", has been to just have everyone agree to defend everyone else without worrying whether they're right-thinking or not, and this is easier than trying to coordinate room for exceptions like Holocaust deniers. Give up on the Holocaust deniers, and no one else can be sure what other Schelling point you've committed to, if any...

...unless they can. In parts of Europe, they've banned Holocaust denial for years and everyone's been totally okay with it. There are also a host of other well-respected exceptions to free speech, like shouting "fire" in a crowded theater. Presumably, these exemptions are protected by tradition, so that they have become new Schelling points there, or are else so obvious that everyone except Holocaust deniers is willing to allow a special Holocaust denial exception without worrying it will impact their own case.

Summary

Slippery slopes legitimately exist wherever a policy not only affects the world directly, but affects people's willingness or ability to oppose future policies. Slippery slopes can sometimes be avoided by establishing a "Schelling fence" - a Schelling point that the various interest groups involved - or yourself across different values and times - make a credible precommitment to defend.

Thinking about this article a bit more, you're missing a very important point. Namely, a "Schelling fence" is often of supreme importance even when there aren't multiple interest groups involved. (Nor even time- or value-inconsistent versions of the same party.)

This is because in most cases of conflict, pre-commitments are difficult to communicate. If you're maintaining some line of defence against an opponent and you're credibly pre-committed to defend even if the cost of defence is higher than the value of the prize fought over, you're safe against a rational opponent who perceives this pre-commitment correctly. However, if you have no such pre-commitment, the opponent has the incentive to mount an overwhelming attack even if the cost of the attack is higher than the prize -- since in that case you'll find it rational to retreat and avoid fighting.

The trouble is, communicating pre-commitment credibly is difficult, since it's always in your interest to assert pre-commitment to defend as credibly as possible, but secretly plan to withdraw if your bluff gets called. So this is where the Schelling points come into play: a conspicuous Schelling point helps create a meeting of minds about pre-commitments between the conflicting parties. Your commitment to defend at that line is credible because by failing to defend it, you lose not only that particular prize, but also everything up to the next strong Schelling point, which may even be nonexistent. (And is certainly harder to use effectively once you have a reputation as a pushover who gives up on valuable Schelling points.)

So, in case of Holocaust denial laws, there might be rational reason to oppose them even if a single Holocaust denier didn't exist. The principle that the government can't legislate official truth is a very clear Schelling point. The same principle modified by an exemption for those cases where the truth is evident and its denial offensive, much less so. Who gets to decide what's evident and what's offensive anyway? So once you've conceded that the government can prohibit you to say that that the Holocaust didn't happen, or that 2+2=5, there isn't any clear Schelling point where you'd draw the line and pre-commit to fight the prohibition.

Or is there? Currently, in the Western world outside the U.S., there are several fairly strong Schelling points based on a general perception about a few extremely low-status kinds of people -- basically, speech restrictions are considered OK if and only if they specifically target these sorts of people. In most places, these groups include neo-Nazis (and right-wing extremists in general) and certain kinds of sexual deviants, and Holocaust denial prohibition is considered OK because it specifically targets the former. However, there is definitely an ongoing slippery-slope effect here -- in many countries, the class of speech restrictions that is vaguely associated with the "right-wing extremist" exception is increasingly used to enforce ideological conformity on a number of issues where dissent from the respectable opinion should not merit that title by any reasonable definition. (And where, arguably, honest pursuit of truth will lead one to disagree with the respectable opinion.)

I'd like to mention that I had an entire family branch hacked off in the Holocaust, in fact have a great uncle still walking around with a number tattooed on his forearm, and have heard dozens of eye witness accounts of horrors I could scarce imagine. And I'm still not okay with Holocaust Denial laws, which do exist where I live.

In part, this is just my aversion to abandoning the Schelling point you mention; but lately, this is becoming more of an actual concern: My country is starting to legislate some more prohibitions on free speech, all of them targeting one side of the political spectrum, and one of the main arguments touted for such laws is "well, we're already banning Holocaust denial, nothing wrong came of that, right?".

There are also a host of other well-respected exceptions to free speech, like shouting "fire" in a crowded theater.

I wonder how many people would use this example nowadays if they knew that it comes from a WW1-era U.S. Supreme Court opinion upholding a ten year prison sentence for sedition against an anti-war activist -- whose crime was to distribute pamphlets arguing that military conscription is unconstitutional under the 13th Amendment, which prohibits "involuntary servitude."

(By the way, speaking of slippery slopes, the following year the same court upheld another ten year conviction for a speech whose content was carefully crafted to remain within the bounds of the sedition laws, but which was still judged to be illegal on the grounds of intent and indirect implication.)

As an interesting side note, the grimly ironic pinnacle of these American WW1-era sedition laws was the ten-year sentence (another one!) against a certain Robert Goldstein for defying the censorship of his film about the American Revolution. The film was deemed to be seditious on the theory that it incited hostility towards Britain, a war ally.

You may be correct, but the speaker in that case was probably referencing the Italian Hall Disaster, a genuine precedent. A rationalist can't just chose to ignore a data point like just because they don't like the way it's normally used.

I wonder how many people would use this example nowadays if they knew that it comes from a WW1-era U.S. Supreme Court opinion upholding a ten year prison sentence for sedition against an anti-war activist -- whose crime was to distribute pamphlets arguing that military conscription is unconstitutional under the 13th Amendment, which prohibits "involuntary servitude."

Wow. The 'fire' thing doesn't even fit well as an analogy in that context. Your country scares me!

My country?! I'm not American. I haven't even been to the U.S. in several years.

(That said, you're Australian, right? I've definitely seen stuff written on LW that is technically illegal in Victoria -- google for "serious contempt for, or revulsion or severe ridicule," with the quotes.)

The fire analogy must be understood in the context of the legal test of "clear and present danger" that the court was upholding. The theory is that just as the shouting "fire" in a theater creates a clear and present danger of a stampede in which people get hurt, so does the anti-war agitation create a clear and present danger of subverting the war effort, in this case by inciting resistance to conscription.

Of course, you may reply that this "clear and present danger" stuff can be stretched this way without limit, but that is the point. (By the way, in U.S. jurisprudence, this standard has in the meantime been superseded by a much clearer one of imminent lawless action, which, whatever its overall merits and faults, has shown in practice to provide for a very strong Schelling point.)

My country?! I'm not American. I haven't even been to the U.S. in several years.

My apologies. I assumed too much from your evident awareness of US internal politics.

I've definitely seen stuff written on LW that is technically illegal in Victoria -- google for "serious contempt for, or revulsion or severe ridicule," with the quotes.

Without at all claiming that examples don't exist it isn't technical illegality that concerns me but actual instances of punishments, along the lines of the two cases of 10 year incarceration.

As you have illustrated, things being legal or otherwise is not too important. Far more important is the inclination of the judge (and the surrounding political incentives) to punish any given behavior. Both of the cases you cite illustrate how easily laws can be ignored by introducing a fully general excuse along the lines of "except when it is really politically expedient to do so!"

Without at all claiming that examples don't exist it isn't technical illegality that concerns me but actual instances of punishments, along the lines of the two cases of 10 year incarceration.

The Victorian law is one of those laws whose real meaning is quite different from its formal one. Read literally, it is a sweeping law that criminalizes anyone who says anything unkind about any religion. (It's literally criminal to "behav[e] in a way that encourages... revulsion or ridicule of another person, because of the other person's... religion," or to "encourage[]... severe ridicule of... [a] class of persons, because of their... religion.") Yet in practice, of course, it's tacitly clear what kinds of people should watch their mouths or else fear prosecution under this law, and who can in turn safely ignore it. (Generally, throughout the Western world, with the U.S. as a lone exception, modern speech restrictions commonly have this form, providing effectively a broad mandate for ideological censorship.)

Note also that a century ago people were tougher and had less to lose, so that much more severe penalties were necessary to get them in line. Also, a criminal or even just an arrest record of any sort is by itself a far more severe and permanent penalty for a respectable person nowadays than back then. Even defending yourself successfully in court will require a ruinous expense for everyone but the very rich, and this cost has gone up way out of proportion with income. So, while nobody in the West is facing ten-year sentences for speech these days, I don't think the chilling effects are much less severe than in the WW1-era U.S.

Edit: By the way, none of these Americans (as far as I know) actually served a full ten-year sentence. They were all pardoned in the early 1920s by Warren Harding under his policy of "return to normalcy."

Edit: By the way, none of these Americans (as far as I know) actually served a full ten-year sentence. They were all pardoned in the early 1920s by Warren Harding under his policy of "return to normalcy."

Yes, but it certainly hasn't won out when you look at the way Woodrow Wilson and Warren Harding are remembered nowadays...

All else being equal (taking only the potential influence of these particular actions on popularity) that isn't encouraging. I don't know enough about US politics to know whether dislike of Harding is at all related to him having a nature such that he would make these (desirable) decisions.

How they're viewed has little to do with these decisions. Harding is seen as a weak President who was manipulated by those around him and who allowed corruption to flourish in his administration. The most famous example of this was The Teapot Dome Scandal. He may also, much like his successor Coolidge, have become associated with the boom that preceded the Great Depression.

Wilson is, unfairly I think, rewarded for leading America during WWI. This is in spite of the fact that he promised to keep America out of the war and managed to lose the peace that followed. Besides upholding sedition laws he did a number of other thoroughly un-liberal things.

That is true, literally speaking. The point, however, is that the qualities that got Wilson celebrated and Harding forgotten or despised in the century since then were actually the same ones that led the former to fill jails with political prisoners and the latter to consider it unacceptable to preside over a country whose jails are filled with political prisoners. Besides, compared to the way things were done under Wilson, holding these petty corruption scandals as a heavy sin against Harding shows a complete lack of perspective.

But here we are getting into a historical and ideological discussion for which this forum is probably not a good place.

So, while nobody in the West is facing ten-year sentences for speech these days, I don't think the chilling effects are much less severe than in the WW1-era U.S.

Yes and no. In the last several decades there has certainly been a troubling trend of disregard for free speech in civil law - i.e. "cyberbullying" kinds of things, where people are now basically able to sue because their feelings got hurt. And you're absolutely correct about the cost of litigation having a strong multiplier effect on the "chillingness" of such suits. But in criminal law, things are definitely MUCH better today than they were in the WW1 era. For one thing we now have a de facto Shelling fence around punishment of speech which is explicitly political in nature (like protesting the draft).

a criminal or even just an arrest record of any sort is by itself a far more severe and permanent penalty for a respectable person nowadays than back then.

I heard somewhere that for the civil rights protesters of the 60s, going to jail had a very different meaning than it does for protester types today. Respectability was a much bigger deal then than now - those people dressed up in suits to protest and be arrested. At the time, the only marginally well-known precedent for being arrested for a good cause was Thoreau. I know people now who are proud of their protest-related arrest records, but that wasn't really a thing before the 60s.

Wow. The 'fire' thing doesn't even fit well as an analogy in that context. Your country scares me!

That era, and those rulings, are pretty widely regarded as the low point of American first amendment jurisprudence. Things have rebounded significantly since then, and, as Vladimir points out, those cases have long since been superseded as binding case law.

Wow, man, awesome kudos for this link. The slope indeed slips the other way; once you allow the supreme court to make fire in the theatre analogies, you can start prosecuting people for 'sediction', which is in direct contradiction with the principle of free speech as necessary for the liberty of a free state.

This. This this this. I feel like the "fire in a crowded theater" example is a pretty painfully outdated one. If you imagine a more crowded theater made of dry wood with no sprinklers/fire extinguishers, it becomes a lot more reasonable to expect people to panic at the thought of a fire.

I think the prevalence of the "falsely shouting fire in theater" quote is a product of usage of that quote in an important freedom speech decision (that ultimately ruled against free speech).

Thomblake suggests convincingly that the quote was referencing a then recent disaster, but you are correct that the circumstances in theaters today are so different that the quote lacks the same impact as when it was written. In other words, the same legal reasoning today would probably be supported by a more culturally relevant example.

For what it is worth, the legal standard on liability for possible harm from speech is different (and more speech protective) than the decision in the Schenk case from which the quote originates.

Wedrifid was saying that people aren't that likely to stampede or even evacuate if someone yells "fire" now. I think he's right. If I started shouting "fire" right now I think the people around me would think I'd snapped and would at the least ask what I was seeing that they weren't.

(If I actually wanted people to listen to me I would start by asking "do you smell fire?" to the person next to me. Two people shouting fire is much less likely to be someone hallucinating.)

Reality is more complicated than that. Grandparent is right about deaths from fire in many parts of the world. The following deals with the fire death rate from 1979 to 1992.

The U.S. fire death rate fell 46.3 percent, from 36.3 fire deaths per million population in 1979 to 19.5 fire deaths per million population in 1992. As shown in Figure 2, however, this trend was not limited to the United States; rather it was international. Of the countries considered, only Hungary and Denmark recorded increases in their rates of fire deaths over that period – all the other countries lowered their fire death rates. The reduction in fire deaths for the United States (46 percent, or 16.8 fire deaths per million population) was the largest absolute and relative drop of any of the countries shown – almost twice the size of the next biggest drop (the United Kingdom, with a reduction of 38 percent, or 9.0 fire deaths per million population).

"These kinds of things" are public perception and, in particular, public perception of risks and what to be afraid of. For these kinds of things single datapoints matter a great deal. Prime example: 9/11.

Public perception of risks notoriously does not care about statistics.

Since rare dangers typically get more publicity than common dangers, we might even expect that under many circumstances public angst may increase as the actual danger decreases (due to the remaining incidents getting overreported).

Any theatre offering access to the public should be able to evacuate all patrons safely in the event of a real fire, thus someone falsely yelling "fire!" simply inconveniences people and should be banned by the owner. There is no need to get the police involved and have this ridiculous example as legitimisation on limits on free speech in a public arena.

There are limits that should be upheld, but not necessarily by police (e.g. someone being slandered could sue rather than have the slanderer arrested.) Incitement to violence may be banned as a pragmatic measure, but that would be my Schelling point (and even then I'm not 100% sure...)

So your idea is to have them stay in there indefinitely as someone might get hurt on the way out?

If you can't evacuate a theatre without a reasonable expectation that no-one will be harmed you shouldn't be running a theatre and anyone who is harmed should sue you (or fire marshals, local council, regulators or whoever should shut you down).

Even if a reasonable expectation that no-one will be harmed during evacuation exists, it doesn't follow that forcing an unnecessary evacuation has no expected costs other than inconvenience (as you originally claimed).

It might be, for example, that most experts in the field accept that theatre-evacuation technology simply isn't expected to reduce the expected cost of an evacuation below .01 deaths, and thus expecting less than that is unreasonable, and this fact is published and known to all theatre-goers, who decide that .01 * likelihood-of-evacuation is small enough to not preclude going to the theatre.

It follows that there's no grounds to sue the theatre, the fire marshals, etc.

It doesn't follow that forcing an unnecessary evacuation has no expected cost.

So your idea is to have them stay in there indefinitely as someone might get hurt on the way out?

That's not at all what I said.

If you can't evacuate a theatre without a reasonable expectation that no-one will be harmed you shouldn't be running a theatre and anyone who is harmed should sue you (or fire marshals, local council, regulators or whoever should shut you down).

Basically what TheOtherDave (hmm, convenient, as I happen to be a Dave as well...) said. A bunch of frightened people moving about all at once are going to present more risk than a bunch of calm people trickling in and out; the question is what we can do to lower that risk. Any security measure is about tradeoffs, and when it costs X to lower the risk by Y of harm Z, and X > Y * Z * chance of an incident, then implementing the measure is bad policy. This calculus is embodied in the decisions made by the fire marshals and the local councils and regulators and whatnot as they put together the local fire code, run inspections, etc, whose goal is not to reduce the risk to zero (or even "absolutely as low as we can go at any cost").

when it costs X to lower the risk by Y of harm Z, and X > Y * Z * chance of an incident, then implementing the measure is bad policy.

Is exactly the point, but you have not defined X. Given that X leads to a slippery slope decrease in all free speech rights (e.g. Gitmo torture reporting, Bradley Manning etc. etc.) then how do you quantify X?

Sometimes the direct harm of X may be less than the others, but the principle is much more important.

This is why we presume people innocent. This is why convicting no-one is preferable to convicting the wrong person. This is why, in short, we have rights!

Which has nothing to say on the possible, actual or long-term harm of removing the rights of free speech in a certain situation - it simply defines (quite well) the other side of the equation.

The criminalisation of free speech is a severe measure and must be as limited as is practicable in scope. All western societies are based on the free exchange and discussions of ideas. The benefit of free speech is so great (as mentioned in the Hustler case) that its restriction must prevent some great harm. As a recent example showed, the right of a Florida pastor to burn a book outweighed the strong probability of his actions leading to a severe cost of injury (death) to US, and other, civilians and military abroad.

Now, maybe you think his rights should have been quashed (I strongly don't), in which case you're consistent, or you must think that the right to yell "fire!" when there isn't one should be upheld as the probability of harm, and the likely amount of harm, are low - or you're applying different rules according to some outside notion not yet mentioned.

I happen to think there is another notion here - intent. The intent of the "fire!" yeller is somewhat irrelevant since the actual danger is, or should be, minimal. The pastor simply wanted to upset Muslims, which is certainly protected under free speech, their reaction is a separate problem. Whereas a mafia don publicly offering a bounty on someone's head is a different ballgame.

I happen to think there is another notion here - intent. The intent of the "fire!" yeller is somewhat irrelevant since the actual danger is, or should be, minimal.

The is a core part of the disagreement. The cost of preventing risk of injury from a false yell of fire is prohibitive for the owner of the theater. So it is reasonable to shift some of the cost of prevention to the person who knows there is no fire but wants to yell fire, in part because the cost of not falsely yelling fire is so low. Further, it is reasonable to expect the potential false-yeller to know that the yell will be believed, cause panic and therefore cause injury.

The Koran burner receives more protection because there wasn't a knowing falsehood in that case. The relevant mental state is not intent to harm, but knowledge of the statement's falsity.

Okay, but what it comes down to is what is the expected reaction of reasonable people in a given situation. If people can't safely exit a theatre then we need to re-think theatres. And safety tests.

If I'm in a theatre and a patron shouts that the popcorn has been poisoned (an intentional lie) then I can't conceive of any action (assuming [s]he hasn't been near the popcorn) other than ejection and ban. don't see why their liberty has to be sacrificed.

Similarly, if the risk of injury is as low as I think it (should be) is then the intent to cause panic is again not an issue for the criminal justice system. Sue them (if you can/must) and ban them for life.

The apparent agreement that a false statement that has an incredibly small chance of causing actual harm, where the harm is unlikely unless the venue is sub-par, should go beyond the basic remedies for the discomfort and damages caused by the injured parties and spill over into denying someone their liberty is worrisome.

I find it's easier to think clearly about this stuff if, when calculating the costs on both sides, I try to forget that I have a preferred answer.

The cost of someone shouting "fire!" in a theatre is what it is; I'm inclined to agree with you that it's not very high, though I think you're trying to make it sound lower than it is. The cost of preventing someone from shouting "fire!" in a theatre is what it is as well. Looking at just the first-order costs I conclude that the costs of preventing it are in general lower than the costs of it happening.

The second-order costs are less clear to me and can easily swamp the first-order costs, though. Mostly it becomes a question of whether there's a reliable Schelling point near shouting "fire!" that I expect to prevent that from becoming grounds for supporting higher-cost speech suppression. I'm less certain about that; and I expect it depends a lot on the specific community, so I can easily see where the "shouting fire" legal principle leads to a lot of expensive bad law, and that on balance we'd therefore do better discarding the principle.

Or perhaps not.
If I were actually interested in activism on this issue, I would start by refining my estimates.

As for intent, I'd say it's at least theoretically relevant. For example, I consider the cost of having prevented all-and-only people who wish to shout "fire!" in a theatre for malicious reasons from doing so to be significantly lower than the costs of having prevented everyone from doing so regardless of their intent. That said, the costs of implementing such a policy given current technology are onerous, so I probably oppose (given current technology) having such a law, although various cheap approximations of it might be OK.

Noting that on the one hand I don't think our actual policy recommendations would be far apart (as pertaining to the issues at hand, at least) , and on the other that I have may objections to particulars your post above, I am going to nonetheless bow out as we are straying much too deep into mind-killer territory for my liking. I notice that you are new here, and point you toward Policy Debates Should Not Appear One-Sided and Politics Is The Mind-Killer, if you have not already seen them. Feel free to contact me privately if you would like to continue any political part of this discussion in another forum.

Any theatre offering access to the public should be able to evacuate all patrons safely in the event of a real fire, thus someone falsely yelling "fire!" simply inconveniences people and should be banned by the owner

A theater than can protect its patrons against a real fire doesn't necessarily equal a theater that can protect its patrons against a false fire.

Nor do I find it more reasonable to ban businesses that are incapable of protecting all patrons against the repercussions of all types of lying. I find it far more reasonable, and much of a "Schelling point" to ban spreading knowingly false information.

e.g. someone being slandered could sue rather than have the slanderer arrested

That's effectively a matter of degree -- you're just saying that the punishment should be a fine instead of a prison sentence. It's not really a difference in kind.

A theater than can protect its patrons against a real fire doesn't necessarily equal a theater that can protect its patrons against a false fire.

That is a patently false statement.

I find it far more reasonable, and much of a "Schelling point" to ban spreading knowingly false information.

And thus the slippery slope becomes a teflon cliff.

That's effectively a matter of degree -- you're just saying that the punishment should be a fine instead of a prison sentence. It's not really a difference in kind.

One is criminal and the other is civil? One is a dispute between two (equal under the law) individuals in front of a (supposedly) impartial judge and the other is the state versus an individual? Quite a lot of difference really.

A theater than can protect its patrons against a real fire doesn't necessarily equal a theater that can protect its patrons against a false fire.

That is a patently false statement.

How do you know this? In the case of a true fire, fire extinguishers may activate, fire exits might automatically open, or perhaps the theater's army of flying robots would come and carry everyone to safety. Or perhaps the theater is designed from such materials that it can't catch fire.

And thus the slippery slope becomes a teflon cliff.

Excuse me? The concept of "knowing lie" isn't a good enough Schelling Point for you?

I'm in favour of banning the act of falsely shouting "Fire" in a theater, for the exact same reason that I'm in favour of banning the act of giving poison to other people while calling it "orange juice"

I don't think you'd have any opposition to treating the latter an act of murder, why are you against treating the former likewise an act of murder?

One is criminal and the other is civil?

This is a legalism, a difference in labelling, nothing else.

One is a dispute between two (equal under the law) individuals in front of a (supposedly) impartial judge and the other is the state versus an individual?

Again mere legalism. In practical terms, it's the same, at least from the point of view of the accused -- you get accused for something, someone is accusing you, if you're found guilty you get punished. Simple as that.

Excuse me? The concept of "knowing lie" isn't a good enough Schelling Point for you?
I'm in favour of banning the act of falsely shouting "Fire" in a theater, for the exact same reason that I'm in favour of banning the act of giving poison to other people while calling it "orange juice"
I don't think you'd have any opposition to treating the latter an act of murder, why are you against treating the former likewise an act of murder?

I believe there actually is a salient distinction between the two. Namely, whereas the harm in the poisoning is the act of placing the poison in the drink and giving it to another person, the act in shouting "Fire!" is in the believing that there is no fire and the harm resulting from the shout. While the distinction would not amount to much for an all-knowing god, in reality it would probably prove difficult to establish what the person shouting expected the result to be, and to determine whether he had believed there was a fire or not. Punishing alarmist statements is indeed a potential slippery slope - if someone shouts "Earthquake!" in the middle of a crowded street and pedestrians panic and someone ends up in the traffic, shall we prosecute this shouter too? Or what if someone proclaims that the nation is under imminent threat of nuclear attack and this results in massive economic disruption as people try to hoard survival-type goods?

The problem here is that it is difficult for a court to assess whether the person actually believed what they said, and whether they anticipated (perhaps a priori rationally) that there would be no negative consequences of their proclamation.

It may also interest you to know that the original "shouting fire in a crowded theater" claim was part of a judicial ruling written by Oliver Wendell Holmes, Jr. in which the Supreme court unanimously ruled that it was a violation of the Espionage Act of 1917, to distribute flyers opposing the draft during World War I, which I think is a suitable example of its slippery slope potential. My general impression is that while there have been real instances of deaths caused by such shouts, most of these occurred before recent times, although I am not too confident in this.

The problem here is that it is difficult for a court to assess whether the person actually believed what they said, and whether they anticipated (perhaps a priori rationally) that there would be no negative consequences of their proclamation.

Courts do this all the time. Further, there's a well developed set of doctrines about when a person is held responsible for consequences that the person did not actually anticipate.

More generally, the quote about falsely shouting fire is not intended to support a particular test for the limits of freedom of speech. Rather, the quote makes the point that speech is not unlimited.I can agree that Schneck's conviction should have been overturned without believing that no pure speech can have legal consequences.

As an aside, the current test in the United States is imminent lawless action, a much more pro-speech standard. Nonetheless, a knowing false statement likely to lead to multiple injuries is almost certainly punishable by the criminal law.

Thanks, that helps update my knowledge of the current standards. I certainly agree that what you say is reasonable, however I do not think that a potential for a slippery slope effect can be eliminated through carefully formulated test or doctrines (merely substantially reduced). For example, it is conceivable that in emergencies the fact that we now accept some restrictions on free speech will make it much easier to accept further restrictions and thus make unreasonable restriction more likely.

Whether that is a reasonable compromise depends on the actual danger of "pure speech" causing negative consequences, on alternative ways of mitigating them, and on the actual degree of the slipperiness of the slope. Personally, based on my current knowledge, I would prefer to pursue various alternatives before resorting to criminal legal action, however that's dependent on actual facts and has little to do with the main topic being discussed.

One is criminal and the other is civil? One is a dispute between two (equal under the law) individuals in front of a (supposedly) impartial judge and the other is the state versus an individual? Quite a lot of difference really.

This distinction breaks down very quickly. Consider Hustler v. Falwell, which limited the scope of civil remedies because enforcement of those remedies violated freedom of speech.

No. If you really believe the public/private distinction is solid, then the First Amendment has nothing to do with private (i.e. civil) disputes. So Hustler should have come out the other way.

In general, American law has really struggled with the public/private distinction. I would say this is because the distinction is not rigorously meaningful - although I doubt most judges would frame it quite that way.

Regardless of the framing, American law recognizes that the situation of "two equal individuals before an impartial judge" includes the fact that the judge is an arm of government, exercising government power. What that means in practice is less clear.

Compare Shelley v. Kraemer ("That the action of state courts and judicial officers in their official capacities is to be regarded as action of the State within the meaning of the Fourteenth Amendment is a proposition which has long been established by decisions of this Court.") with Schiavo v. Schiavo (holding that a state judge ordering the removal of a feeding tube is not state action).

I've also started an argument on some other forum, to test some ideas, with regards to the 'harm principle' (in law). Most of the laws of free countries do conform to harm principle, even though it is not in constitution and a few laws don't (usually for quite bad reason and with very ineffective enforcement). But if you try to bring it up you get slippery slope arguments along the lines of "if we start legalizing harmless behaviours we'd have to legalize driving on other side of the road". Try talking to authoritarians and you can see them argue the slippery slopes the other way.

It must be noted though that there's much longer way to slip in the direction of disallowing speech, than in the direction of allowing speech.

Another approach to (or rather away from) slippery slopes is to see the entire slope as a single thing à la TDT. Gandhi, contemplating his willingness to make the trade to become 95% Gandhi, can also foresee that 95% Gandhi would make a similar trade to 90% Gandhi, and so on. So his first decision is acausally linked to the whole of the slope, and to decide to take one step is to decide to go all the way.

The concept predates explicit TDT and can be found in popular wisdom: how often have I heard "there is no just once" in fiction, whether a policeman asked to break the rules just this once, an alcoholic offered just one drink, etc. Kant's Categorical Imperative is similar.

Cf. the maxim "Everything you do is a decision about who you want to be", or the outside-view version, "The way a person does one thing is the way they do everything."

So his first decision is acausally linked to the whole of the slope, and to decide to take one step is to decide to go all the way.

(emphasis added)

No no no. His first decision is causally linked to the whole of the slope. If you draw out the DAG of causation, there's an arrow going right from "became 95% Gandhi" to "became 90% Gandhi", and an arrow going from "became 90% Gandhi" to "became 85% Gandhi", and so on (with some intermediate nodes depending on resolution).

Thanks for noting the connection to Kant; ADT's minimally-metaphysical yet deontological approach, i.e. its Kantian approach, is its hallmark and triumph. (TDT goes heavier on the metaphysics and is weaker for it.)

Note that Kant actually claimed that he was not preferring one consequence over another, he was finding a self-contradiction in one consequence, and no self-contradiction in the other.

That is, "you should not steal" because, at the end of the slippery slope, there is a self-contradiction, something like "if everybody ought to steal, what does theft even mean?". (I'm trying to give Kant a fair shake, though I think he's wrong.)

I'm really not very familiar with Kant, but I guess I always thought to frame it like, after an infinity of time certain norms will defeat themselves, and other norms will reinforce themselves, and if we are to support a self-defeating norm then that's like choosing to become counterfactual. Then endorsing a self-defeating norm seems metaphysically but not phenomenologically possible, and since Kant didn't care about metaphysics, it's straight up impossible. Or something, agh. But anyway it looks ADT-esque, except that Kant had a hard time with meta levels for some reason.

I don't think it's right to say that Kant didn't care about metaphysics. Given that his work on ethics was Metaphysics of Morality and that was based on the more-metaphysical Groundwork for the Metaphysics of Morality. Whether one can choose a norm that is inconsistent, is a question for the noumenal world, not the phenomenal world.

I think you are dismissing the abandoning the power of choice argument unfairly. I'll try to give it a better formulation than you did.

There is a decision to make. The question is not just "A or B?" It is "How shall this type of choice be made?" and "Who shall make this type of choice?"

Changing how decisions of this type are made and who makes them are dangerous. "Holocaust denial is verboten," implies "There are authorities who decide what beliefs are acceptable." and "Individuals cannot be trusted to seriously consider all alternatives for belief." The second is true, because by removing the ability to reject the holocaust removes the ability to consider if the histories are reliable.

For the Civilization example. "I should decide on when to go to sleep based on a prior rule I accepted." is a different principle than "I should decide on when to go to sleep based on my current enjoyment of whatever I am doing now."

Admittedly, I rarely make arguments of the slippery slope form. I prefer to point out the toxic principles being accepted.

A thought inspired by an exchange upthread with Vladimir, but more general than what we were immediately discussing:

It seems that (e.g., political) extremism may be a result of a certain perception of where the Schelling points are and an application of meta-level thinking to the slope, even where basic preferences aren't changed much. Suppose that it is 11:30 and you are playing Civ. You want to play until 11:40 and then stop, but you know that if you do you'll want to play until 11:50 and then stop, etc.

If you think everything is a nice round number, you can just say "I'm going to stop at 11:40" and then do it. This is great if you're not lying to yourself, which you probably are. If you think :00s and :30s are nice round numbers, you can compare how you feel about stopping now, 10 minutes earlier than your current ideal, to stopping at midnight, 20 minutes after it. Trivially so for whatever other round numbers you might see, &c.

But suppose to yourself: "but why should my night be dictated by what I think at 11:30?" Well, because that's who you are at this point in time, and thus whose desires reason consists in fulfilling, obviously. But: you are in a sense in a community of yourselves who will be making this decision for many nights in the future. And: perhaps you have preferences about your preferences not looking/being arbitrary - you look at your 11:00 self and sneer at her ignorance - wanting to end at 11:10! - and at your 12:00 self in horror - is this where we are headed? - but then realize how you must look to them, and reconsider. Even if your round numbers are every 10 minutes then you could stop at 11:40 like you naively prefer, you also realize that if you consistently applied whatever rule you're about to, you wouldn't get 11:40. So the choice is really between uninstalling the game and never sleeping again. If this tendency exhibits some pull and you're hyperbolically discounting, then the larger the distance between your perceived round numbers the more sense it makes to go all-or-nothing (i.e. if you place 12 hedons on being non-arbitrary, then if your round numbers are every ten minutes ending 0 minutes from your preferred time and being abitrary may be clearly better than never playing or never sleeping and being consistent, whereas if your round numbers are on the hour..)

This is consistent with most of my (our?) prior beliefs about the tails of the political spectrum: that compared to moderates extremists are more interested in and familiar with the perspective of other times and cultures (even ones with politics "on the other side",) less socially connected (to people in their own time and culture), prefer System 2 to System 1 reasoning, like big abstract ideas, &c. I don't know if this is just a clever (or not all that clever) reformulation of existing commonsensical explanations for these things or if you could think of testable predictions that would distinguish them.

If you think everything is a nice round number, you can just say "I'm going to stop at 11:40" and then do it.

Meh. I just say "20 more minutes" and set up an alarm timer. Pomodoro technique FTW. (And when the alarm goes off, if I still want to do what I'm doing, I halve the time and restart the timer. This way, the total time I waste can't exceed twice the original time I used, in this case 40 minutes.)

Great post. Very clear and concise as usual. I recently read an interesting article by Eugene Volokh on slippery slopes focused specifically on gay marriage, which you can find in pdf form here. (If you don't like pdf's, the title is "Same-Sex Marriage and Slippery Slopes.") Interestingly, he also discusses the US's first amendment as something like a Schelling point, though he doesn't use the same terminology.

In parts of Europe, they've banned Holocaust denial for years and everyone's been totally okay with it. There are also a host of other well-respected exceptions to free speech, like shouting "fire" in a crowded theater

From what Volokh says in the article, it seems that many countries aside from the US don't have as strong of protections for freedom of speech. E.g., in Canada and Sweden ministers have been prosecuted for comments condemning homosexuality.

In short, a Schelling point is a point that everybody agrees is an “obvious” cutoff point. That knowledge helped me understand this article’s point that Schelling points make good fences to precommit to because you can’t justify moving the fence anywhere else later – the other points are not nearly as “obvious”.

Very good post! I feel like I understand the concept of slippery slopes much better now. The breakdown into different categories of "slippery slope argument", and cases where they would be valid, is one I find especially useful.

It does make me wonder whether the existence of "slippery slopes" is based on the flawed design of human brains, i.e. hyperbolic discounting, and just the general tendency to alter beliefs for self-consistency or because they sound/feel better. (An example of this would be a real-life version of Gandhi's pill, where starting out with a small not-very-bad act which someone can justify within their moral system, like stealing candy, could lead someone to be more comfortable with stealing in general and end up stealing much bigger things.) Would a non-human 'perfectly rational' alien, one that didn't hyperbolically discount and had no tendency to automatically update their beliefs/moral system so that their past actions weren't evil, still need to worry about slippery slope arguments?

Would a non-human 'perfectly rational' alien, one that didn't hyperbolically discount and had no tendency to automatically update their beliefs/moral system so that their past actions weren't evil, still need to worry about slippery slope arguments?

Not from hyperbolic discounting or value drift. Maybe from other sources, like the coalition argument presented by Yvain.

I think I can describe the 'slippery slope' to an alien and I think this description offers an obvious (if difficult) solution.

The 'slippery slope' is what we call a situation in which good judgement and a certain algorithmic response to something correspond in one case, but not in others, such that following that algorithm in similar cases will cause us to diverge from our good judgement at some point. 'Slippery slopes' come up when our good judgement about something is partially but not entirely captured by a particular algorithm.

Our solution to slippery slopes in legal settings is the institution of the judiciary, who are supposed to make sure a law is applied in such a way that is consistant with good judgement rather than with the letter of the law, wherever these conflict. This is how we approach slippery slope problems generally, and it works so long as those in charge of applying algorithms have good judgement, which is common enough, if imperfect and difficult to teach.

Schelling fences are patches or qualifications on algorithms which attempt a better approximation of our good judgement, and while they're useful, they'll never be ultimately sufficient unless there actually is an algorithm which just is good judgement in general or in some specific sphere.

Or could precommit: he takes the deal every time, sending something like 100m to charity, saving hundreds of thousands of lives. He unfortunately kills one person and goes to prison for life, but that's still net hundreds of thousands of lives.

(This is too utilitarian for the real Ghandi, of course, who told the Jews to just let Hitler kill them.)

By the time Gandhi had taken the deal 99 times, though, don't you think he might be less inclined to behave so altruistically? 1%-Gandhi would additionally know that he was on his last chance to become a millionaire, which might help sway him further.

That does not follow. As Giles suggests, the UK does not have a law against Holocaust denial, and the UK is the relevant country for libel tourism, which is the only phenomenon you linked to.

Furthermore, the UK standards for libel are very old, and there has been some success in the UK in reducing them. This is partially in response to pressure from the US, which no longer extradites for speech violations that are not illegal in the US, in direct response to libel tourism.

I'd link to a reference with details on all this, but you already did.

Some nations can establish Schelling fences and others can be on slippery slopes. The strategy of the nations with Schelling fences would depend on the extent to which they care about the other nations.

Slippery slopes legitimately exist wherever a policy not only affects the world directly, but affects people's willingness or ability to oppose future policies.

Isn't this all the time, though? Whenever a policy changes, if nothing else, the incumbent policy changes, which will affect people's willingness or ability to oppose future policies. Looking at the history of politics and law, it looks like slippery slope arguments are right more often than they're wrong.

Senses of history are vague, but still informative. It's not clear to me there's much value in digging up examples.

preferably ones from long ago

I don't consider 1950 to be long ago.

that not all slippery slopes lead to bad outcomes

No, and I did not mean to imply that they did. Many intentionally begin slippery slopes to lead to outcomes they like; foot-in-the-door techniques can be seen as an example. The takeaway is that the slippery slope meme doesn't appear to actually be fallacious- if you think that A will increase the chance of B, and you dislike B, it's often the correct strategic move to oppose A, even if you think A in isolation is a good thing. The challenge is getting the correct model of how A will impact the chances of B.

I don't think we disagree here. As far as 1950 being "long ago", my point was that I picked examples that I really don't expect to be live issues for Less Wrong readers; there were other issues being discussed in 1950 that are still subjects of disagreement between LW-type people, and those I shouldn't use.

Many very smart people wouldn't unreservedly agree that the Terror was bad, either. If you're far left enough to cheer the Terror or far right enough to boo civil rights or rebel in a clown suit enough to do both, you should be used to not being the default audience and practiced at separating such "obvious" examples from the formal role they play in the argument.

You are ignoring the fact that the historical developments commonly known as "civil rights" have in fact led to a progression of ever more extreme policies (i.e. a slippery slope) whose present outcome is controversial even in the mainstream. This is indisputable no matter what position (if any) you happen to support in these controversies.

This slippery slope can be roughly described with the following progression:

2: Libertarian/classical liberal position: procedural equality for everyone as far as the government is concerned, freedom to discriminate (or not) for private parties.

3: Prohibition of overt discrimination even for private businesses and organizations.

4(a): Affirmative action -- the government (and private parties under its influence and pressure) actively try to equalize statistical outcomes across groups by favoritism towards members of groups that do worse on average.

4(b): Disparate impact doctrine -- even if there is no overt discrimination, unequal statistical group outcomes are considered as evidence of discrimination by themselves, and any institution that produces such outcomes can be held legally liable on that basis alone.

While 1-3 are no longer controversial in the mainstream, 4(a) and 4(b) are still matters of intense public controversy. (Admittedly, for unclear reasons, 4(b) gets far less publicity than 4(a), despite its arguably even greater impact in practice.)

Yes, you're right. (And if we like we can extend this slope further out until it includes the Terror, and tada, we've constructed the classical one-axis political spectrum.)

Obligatory face-saving : I still think my claim stands that people (especially "very smart people" like LW members consider themselves) should be able to read the comment, recognize the formal nature of the argument, substitute in slopes they themselves thing are good or bad, and then evaluate it on those corrected terms, even if we generalize it to include normal people and not just nutcases like me or you. But maybe I shouldn't think it stands, because Will (who is very smart, and a nutcase to boot) apparently can't think of any self-reinforcing social changes that he thinks are good. (Or maybe he can, but lays emphasis on universal agreement for some reason? Idunno.)

apparently can't think of any self-reinforcing social changes that he thinks are good.

(I'm very, very bad at this sort of coming up with examples, so I don't think my inability to come up with any is much evidence for anything. I'm also very, very bad at finding physical objects amongst other objects, e.g. looking in the fridge for a certain jar. I strongly suspect that those two skills are strongly related.

Eliezer also claims to be very bad at coming up with examples and has told an anecdote about his inability to find things in the fridge (which he then ascribed to males in general---there are many reasons to be skeptical of the generalization). I suspect something interesting is going on here, and I tentatively wonder if it has to do with damage to, or atrophy of, the dorsolateral prefrontal cortex.)

Hmm, its curious. I am pretty good at coming up with examples or picking out items from crowded environments. Well, for the social changes... what's about gradual abolition of religious fundamentalism? It can be self enforcing (just as introduction of fundamentalism is; instability implies self-enforcing effects both ways).

In general if you can come up with some self-reinforcing social change that you think is bad, the same change, starting from the bad state (assuming that it can start at all), would be self-reinforcing in the good direction. A steel object falling off from under a magnet is a self-reinforcing process - the further it falls, the lower is the attraction - and so is the steel object snapping onto a magnet - the closer it gets, the stronger is the attraction force.

edit: ahh, i looked up in comment thread. Indeed, the problem is that it is hard to keep unstable process in equilibrium, and the self-reinforcing processes go too far. At same time, if you take a terribly religious population where we burned witches, or where they stone the rape victims to death, it is easy to imagine that on the other end of the slippery slope - if the slope is at all inclined in the other direction - the life is massively better.

I made a magnetic levitation device once - it would suspend iron nail under electromagnet. It seems deceptively simple - when nail goes up, turn off magnet, when nail goes down, turn it on - but if you do so you get rapidly increasing oscillations - you have to have a circuit that blends in first and second derivatives of the position into the control signal. A great deal of complexity for a very simple unstable system.

Indeed, the problem is that it is hard to keep [an] unstable process in equilibrium, and the self-reinforcing processes go too far. At [the] same time, if you take a terribly religious population where we burned witches, or where they stone the rape victims to death, it is easy to imagine that on the other end of the slippery slope - if the slope is at all inclined in the other direction - the life is massively better...

...It seems deceptively simple - when nail goes up, turn off magnet, when nail goes down, turn it on - but if you do so you get rapidly increasing oscillations - you have to have a circuit that blends in first and second derivatives of the position into the control signal. A great deal of complexity for a very simple unstable system.

This is the best one-paragraph technical argument against "small-c conservatism" (social, cultural, etc) that I've ever read.

Edit: "the best" doesn't necessarily mean "totally overwhelming"; I just find it a very good illustration of the inherent problems and opportunity costs.

This is the best technical argument against "small-c conservatism" (social, cultural, etc) that I've ever read.

If this is the case, i.e., if this really is the best argument against conservatism you can come up with, it strikes me that you should become a conservative. Notice that this type of argument is even stronger against anything else, i.e., what makes you think you can manage social change?

I made a magnetic levitation device once - it would suspend iron nail under electromagnet. It seems deceptively simple - when nail goes up, turn off magnet, when nail goes down, turn it on - but if you do so you get rapidly increasing oscillations - you have to have a circuit that blends in first and second derivatives of the position into the control signal. A great deal of complexity for a very simple unstable system.

Tangent: A similar problem was described in Sebastian Thrun's Udacity CS373 couse with respect to steering a self-driving car. It seems the similar principles should apply, except that the distance from the magnet will change the effect of gravity on the nail, which makes the problem more complicated.

I'm very, very bad at this sort of coming up with examples, so I don't think my inability to come up with any is much evidence for anything. I'm also very, very bad at finding physical objects amongst other objects, e.g. looking in the fridge for a certain jar.

FWIW, me too, on both counts. Though I don't classify myself so much as very bad at finding physical objects anymore, since I default to systematic search pretty quickly, and while it's slow, it almost always works. Interestingly, I noticed I can do it the 'normal' way when on Adderall - it feels almost like having a HUD that's highlighting relevant objects for me (very useful when driving a car).

Good point, but still: does anyone know of any slippery slope [ETA: by which I mean a cascade of self-reinforcing changes in laws or social norms] that most everyone can agree was clearly not-bad? I ask because there are various theoretical reasons why one should almost never expect slippery slopes to have good consequences, but if empirically that's not the case then I need to revise my sociological and historiographical models.

(ETA2: My bad, I confused levels of abstraction; I agree with the criticisms that such an analysis is unfeasible even if possible.)

Aren't you smuggling in the conclusion? Incremental change that builds on previous changes is generally called a "slippery slope" only when the consequences are undesired. Is the gradual increase in homosexual rights good? Then it won't be called a slippery slope.

More generally, there aren't many changes that "most everyone can agree was clearly not-bad." If everyone thought it would be a good idea, society wouldn't have been doing things some other way.

Could you elaborate on these theoretical reasons? Because obviously the desirability of a slippery slope isn't a relation between the slope and possible desirers, not a property of the slope as such, and it's difficult to see what dynamics of slopes in action could be affected by the attitudinal relations of later persons towards them. Bad from the perspective of those who initiated them, perhaps?

Since history tends to ebb and flow even when it does have a secular direction, examples of self-reinforcing changes in laws or social norms can be found sloping in both directions across any dimension, so if e.g. you think that civil rights was bad, it is not hard to find periods and places where movements in the opposite direction had a self-reinforcing nature. So leaving aside very strong formalist conservatives who oppose changes in laws or social norms a priori, even if there are no slippery slopes that everyone considers good, I would expect that every person would be able to see at least one slippery slope that is by their lights good.

Seems to me that rationalism as a living ideal is a slippery slope with a positive outcome. Once someone takes the initial steps to use rationalism, they then seek to learn more about rationalism, they practice it more and they become more effective and efficient at utilising it.
That looks like a slippery slope to me, but obviously one that has a different outcome type than a traditional negative outcome orientated slippery slope.

As others have said, this seems like a confused question. The legalization of interracial marriage in the US would seem like the obvious example, but I don't know what you want to count or not count as part of the trend. And I'm just guessing at how to interpret "most everyone".

Sorry I may have been unclear, the quote means that when accused of libel a defendant can be exonerated if they prove the statement to be true, however damaging it might have been shown to be by the prosecution.

So to count as libellous a statement must be both false and have done provable damage to reputation. As such the easiest way to prove a statement is not libellous is to show it is true.

Rather than, how I think you interpreted it as meaning, that when libelled one should tell the truth in response.

Regarding what you call abandoning the power of choice, here is an example from HPMoR that looks more like a slippery slope.

The point being, said his inner monitor, it's getting worse literally by the minute. The way spies turn people is, they get them to commit a little sin, and then they use the little sin to blackmail them into a bigger sin, and then they use THAT sin to make them do even bigger things and then the blackmailer owns their soul.

Didn't you once think about how the person being blackmailed, if they could foresee the whole path, would just decide to take the punch on the first step, take the hit of exposing that first sin?

This is somewhat more than a slippery slope. It isn't just that large decisions seem easier to make, there is more force to ensure they will happen. The incentives are such that without any slippery slope reasoning and each breach seeming to be just as bad at the end as it did at the start the steady corruption would still occur.

There is a potential negative consequence, when groups are together against a reasonable project, but can not agree on the alternative they actually prefer. That can be viewed in action in Germany with big infrastructure projects. In particular at the moment with the reconstruction of the Train Station in Stuttgart. Many groups are against the project, but have not compatible ideas on what to do instead.
If contrarian groups get better at coordinating their protests you might end up in a situation where no productive project is possible any more.

In politics it leads to a part of the population to always vote for the other guy.

I never thought I would hear a plausible defence of slippery slope arguments.

An interesting analogy is with the Sorites or 'heap' paradox, and mathematical induction. In the paradox you show that one grain of sand is not a heap, and that two grains are not a heap, and three.... so you generalise that for if N grains of sand is not a heap then N+1 grains is also not a heap. Therefore 10^1000 grains of sand cannot be a heap, and there are no heaps!

Obviously the problem is that the premise isn't true for any arbitrary N, (unlike cases of mathematical induction where you prove them to work for an arbitrary number).

Similarly with slippery slope arguments, proving that you can move between two points does not mean you can equally easily move to any other point. For example it is plausible that if abortion term limits were changed from say 16 weeks to 17 they might be more likely to move t0 18 in the future. But That doesn't logically imply we will therefore kill born babies.

Edit: Not sure why this has been downvoted so much, did I misunderstand something about the post?

Thanks, I've seen that before. What interested me about the reaction to it was every commentator decried them for suggesting babies should be killed, said that it would give weight to the arguments of anti-abortionists or that it showed how out of touch academics were with public opinion. But no-one gave an argument in response about why an 8 month abortion and a born baby are different in a morally relevant way. I had underestimated how much in general public discourse even discussing a morally condemned act was itself condemned.

In the context of slippery slopes, again this is moving between two adjacent points not showing you can just as easily move to any point on the scale.

Obviously the problem is that the premise isn't true for any arbitrary N

This is a tangent, but...

This is certainly not obvious (I submit that if it were, the Greeks would have noticed) and I don't think it's true either.

Treating heapness as a boolean, the Sorites paradox indeed implies that there are no heaps, or that any number of grains is a heap. If N grains of sand together are not a heap, then N+1 grains of sand also are not; the piles are visually the same, and so anyone who knows what 'heap' means would look at them and classify them as both "heap" or "not heap". I submit that if you ran that experiment for different values of N (showing each respondent only one instance of N and N+1), you would find no N for which most respondents classified one as a heap and the other as not a heap.

Since this is a paradox, we know there's a problem with one of our assumptions. These days, the obvious one is that heapness is not a boolean. There's a cluster in thingspace we call "heap", and some things are clearly part of the cluster, like a pile of 2000 grains of sand, and some things are clearly not part of the cluster, like a single grain of sand.

Then to do our mathematical induction, we must agree that for any arbitrary N, if N is clearly part of the cluster then N+1 is also clearly part of the cluster. But there is some point at which you become uncertain. I submit that there is some N such that N grains of sand is clearly not a heap, and N+1 grains of sand may or may not be a heap; also, there is some N such that N grains of sand may or may not be a heap, and N+1 grains of sand is a heap.

Though really if we wanted to formalize this, we'd probably set different thresholds depending on whether we're adding or removing grains of sand; the N at which something stops being clearly a heap is lower than the N at which something starts being clearly a heap, and we might even cut out the "uncertain" category from this model. And this would probably match people's intuitions if they watched people adding or removing grains of sand and were told to classify.

"Refuse to adjust your utility function because you will no longer be you, unless the adjustment improves you in terms of your own values" seems to be an important general principle, and it should be enough for Gandhi to turn down the pill.

i really enjoyed reading this thank you. best article i've read on here so far. fantastic examples and the examples really 'make' it - i shall try not to plaguerise but from now on when arguing about this stuff i will definitely give examples that show the progression.

the big one here in europe at the minute is 'hate speech' - arguments between whether it's an exception that's dangerous and damaging enough to be worth an exception or whether it's a dangerously low point on that slippery slope.

Depends in the inferential distance to the "demonstrably" part. But otherwise yes, frequently even when the policy is "demonstrably optimal" with respect to something that's not quiet the right utility measure.

I feel like the following game-theoretic model might be illustrative. Suppose that you have N people ordered by radicalness. These people will repeatedly vote on the proposition of killing the most radical among them (with a simple majority needed to succeed). Assume that each person's preferences are such that they would prefer to have people who are more radical than they are killed but not at the cost of being killed themselves.

This is a game of perfect information and is not hard to analyze. The result is that people will be killed until a power of 2 are left at which point the more radical half of those remaining will all vote to spare the remaining person (because if this person was killed, the same logic dictates that all of them would also end of dieing). This shows how a Schelling point can be established with no communication.